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Topic: Legality of timber frame construction (Read 2412 times)

What I'm getting at related to our situation in particular is this:our wood is "free", if we don't count opportunity cost, so our plan would be to "oversize" sufficiently to avoid grading.

Our 175 acre forest is loaded with white and red Oak, in particular.

You've been threatening to come up here, Don? We need to get together with the guy in Northern Virginia and build those bleachers for watching me getting crushed by a 5 ft tree falling on my SSL & its tree saw, or at least my jumping out & running really really fast. We just transported the Liebherr track loader to the farm, so now I've got some serious pushing power with its 34,000 #. The only problem is destroying the root ball, cutting down regeneration.

That 4x12 you mentioned must've been really bad. What about it made you want to pull it out?

My experience:When timberframing, your wood is going to be green. You cannot Kiln Dry hardwood timbers 4 inches and thicker because you can dry the outer inch, but the inside of the timber will still be green. I you purchase Doug fir, which is non native unless you are in the pacific northwest, they do kiln dry those, and they do better in a kiln than hardwood, but I think the center of your timbers are still going to retain moisture.

There's nothing wrong with using green timbers. It has been done for thousands of years. It takes big timbers dozens of years at least to dry to ambient conditions. Most of the movement from drying occurs in the first 1.5 years though.

Your timberframe should be engineered, not for the sake of the code/building department, but so that your timbers are sized appropriately, and the foundation is correctly engineered. This is a must in my book. You should not intentionally "overbuild" because that can cause other problems and costs. When the engineer goes to analyze your frame, he will use material properties for the wood you are using. Sometimes, for simplicity, he'll use properties for the weakest wood you are using. For example a frame where white oak, mixed oak, walnut, and beech are used, the engineer did his calculations using the properties of the beech.

Grading timbers. In my area, the timbers do not need to be grade stamped. Grading is very important though for YOUR frame. By grading I mean a visual grading by an experienced timberframer. You can learn to do this too. This is not a grading for "grade 1", "grade 2", etc, but rather grading your timber as to whether it is suitable for a particular area of the frame. For example, posts can often tolerate more knots, wane, etc, while horizontal members like tie beams or rafters must be far better. Recognizing the location of defects and where they would fall in a tie beam is very important. A defect in the middle bottom of a tie beam is very bad. A defect towards the ends may be just fine, or on the top. Once you have timbers in hand, you need to look at them and decide where they go, how they will be oriented, and whether or not they will be acceptable. You may have to cull a few timbers and order additional if they don't make the grade.

The inspector. The ones I've dealt with are not all that experienced when it comes to timberframing. They recognize that it is traditional and works, but defer to the engineer and the timberframe guys themselves as being far more knowledgeable. When they see the quality of the work being done, they are more assured that things are being done right or being overbuilt(more safety margin). That may or may not actually be true, but that has been their perception.

Some counties are very strict, rule oriented, and cannot think or make decisions outside the box. Sometimes you can just get the kind of inspector/code guy that is disagreeable, or overboard on relying on rules on paper. Hopefully you'll get lucky and find a reasonable person that will work with you. In their defense, they are covering their butts too. They have to justify why they allow something that may not be in "the book" specifically. The book is written around stick framing as that was and is what is predominant. So sometimes we're trying to fit our round peg in their square hole.

Logged

Anything someone can design, I can sure figure out how to fix!If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

Thank you for the detailed comments, Swampdonkey. We are going to involve a timber framing expert at some level, and definitely will get our plans stamped by an engineer whether the building inspector requires it or not. The timber frame company most likely to help us has engineers on staff so we're in good shape there. Based on what I know of their work, and on that of the others we're talking to, the building inspectors around here are completely comfortable with them. And I've spoken with the building inspector in this county already; he indicated that experts will prevail with him. Nice guy, lives nearby.

Albemarle County and Charlottesville are right next-door, and if you can satisfy them you can satisfy anybody.

We have almost no softwoods on our property except for Seiter (Siri is stupid, go on what it sounds like), so we will likely be building with oak and related. when I say we will oversize, I mean oversize enough for our structure to be qualified using "grade 2", and satisfy the engineer & building inspector.

One of our goals is to do some trading with the timber frame company, wood for work. So far, we have two good healthy fish sniffing that bait.

I wonder how many building inspectors know wood species well enough to distinguish when looking at a great big timber. I can smell oak & cedar, but I can't tell you which precise one it is.

I'm well settled on the green timber question, though my mind remains open to alternative views. In other posts I have marveled at how even experienced ArchiText don't know that green timbers work. I don't guess Siri is a member of AAA , try again Siri, AIA.

Don, P, you had expressed some disagreement on the green timber framing question as well. If you care to explain more, I'd love to read it. Your posts are generally some of the best on this forum on any given day. I am sure I am not alone in appreciating that.

I thought the comments about types of defects was really good. I'm still waiting on Don to tell us what was wrong with that 18 foot timber that he want to pull out. Pictures would help .

Do remember the title timberframer is one that someone applies to themself. It may or may not mean they have been trained to grade or know what they are looking at. My oopsed timber was installed by timberframers. Hopefully they are going to the upcoming grading school. The same can be said for an engineer, they may or may not be qualified to grade but they do carry insurance and are supposedly working within their area of expertise.

I'll try to get a pic tomorrow. It isn't horrible but it is not on grade, I spec'ed #1 or better. The job is ag exempt. The only timbers that have been checked were done so by me after I was concerned with some of the dimensions coming out of the timberframers' "from experience". They were not happy with the sizes I was coming up with. Happily a friend who is an engineer came by to see the job while we were having one of those discussions and I asked him to check me. He asked why I felt the need to cut it so fine, he would have gone up another size.

Steel is "graded" to various strength properties at the mill, analogous to commodity lumber. There are no backyard steel mills producing structural steel. The engineer comes in at fabrication design and implementation just as with wood.

The inspector does not know what he is looking at, he defers to the gradestamp. He does have the right to call for a reinspection. The overseeing agency would then send out their check grader. I've had bootleg stamped lumber show up on a jobsite as well as unstamped lumber, both from lumber suppliers trying to save a buck and slide stuff through. The unstamped was garbage and went back, the bootleg was of excellent quality and I took the risk that the inspector wouldn't look at the stamps or if he did wouldn't know. I did tell the driver to let the folks upstairs know that wouldn't happen again. I don't agree with the law but am subject to it.

Green lumber and timbers. Green wood shrinks. No you cannot predict how it will react as it dries nor can you account for all of it. The only advantages of using green wood in construction are for the benefit of the builder or supplier not for the benefit of the building. That is a decision that needs to be weighed when working either way. I've done a fair amount of both.

Interesting links. I'm not familiar with Timbersmiths but it looks like they do some good work. Dreaming Creek is only about five miles from me and I've been following their work. They have really grown since they got started back in the early 90's and have quite a reputation now. Either one looks like a good resource for you.

Dreaming Creek has a beamery in Floyd county, so you guys up there may know something about them.

Here is the offending joist. The rafters in the top of the frame are actually up on another beam well above this joist. Notice the knot across the lower third of the joist.

Here it is from the other side, sorry my viewer is getting dark so I didn't get the shot centered well, that's it clipped in the top of frame with the next 2 joists below it in frame. You can see this knot is taking up basically the lower third of the beam. The bottom strap of good clear straight wood is completely missing, it significantly weakens the timber. There is no other call to make, pull it.

As a Building Inspector I have found that because an Engineer has stamped the plans does not guarantee that that the design complies with code.

I have reviewed two different plans with design errors, the first specified undersized floor joist and the second had undersized rafters. The first was easy to resolve, a call to the engineer and the plans were corrected. The second involved too many people, a log home company and the buyer of the kit. Told the buyer that stamped plans were required so they called the company and Presto! stamped plans appeared. The company is based in the south and the home was delivered to northern NY. Unfortunately the Engineer, who was licensed in NY but residing in the south never looked at the snow load. I denied the building permit and all hell broke out. In order to use the designed rafters they needed to be doubled up and spaced 16" o.c. vs 24 o.c. The buyers argued I had to approve the design because they had been stamped ( at considerable cost to them) and when I asked who they would blame if their roof failed they saw my point. There still is a lawsuit over which party will pay the extra costs incurred.

Jwilly, this is what I meant about the inspector having the final say.

But you had valid grounds to not approve the plans. "Engineer has made a mistake" or "The plans aren't suitable for our climate / weather". We have similar standards for wind loading, so a plan that would be approved for my location likely wouldn't be approved for a hill over Wellington city where they would expect 100+ mph wind gusts.

You didn't just reject them on a whim, and if it ends up in court, you can explain to the judge why.

Did that experience in the Adirondacks involve #1 lumber required? this is probably a different issue since it didn't involve number grading, I realize upon reflection. Of course the same thing could happen in the opposite direction, building inspector could approve the plans only by requiring something the engineer found to be in error because, for example, he or she did not understand the type of building. A builder with 43 years experience in our area told me this morning that he struggled to make our county inspector understand a very unique timber frame home that he was building, complicated by the fact that a timber company from Vermont put it up, the frame that is, with help from his laborers.

an aside: the timber frame company promised to send a crew. instead, they sent one person, who then asked for help from the builder, the laborers. They had no experience and no clue, no wonder the cost started rolling up. This the general contractor admitted.

Harvey shook me up back telling me the cost of building just the timber frame, for a 2500 square-foot house, over $100,000 parts and labor. He felt a lot of the cost was engendered by parties involved who didn't understand things; he admitted being part of that. I think a lot of it was transportation cost Vermont to Virginia. Ask me why I want to cut my own wood.

A quick note to Ian: wind loading is becoming an issue for inland US as well. I am told the BOCA code has over only fairly recent years been in revision to "load" (no pun intended) all buildings with increased hurricane protection requirements, especially with regard to roofing.

I can relate on a personal level. The eye of hurricane Isabel passed directly over our house in 2003, and we are well over 100 miles from the coast. Fortunately we lost only trees and some minor damage to our house and our rental property next to our historic log cabin restaurant.

Bracing requirements on buildings have certainly tightened up with each code cycle. In the late 90's BOCA, SBCCI and the Uniform code all morphed into the current set of nationwide international codes, the "I" codes. If stick framing a residence you generally fall under the IRC, int'l residential code. This is a prescriptive code that "prescribes" approved methods and means that do not require engineering. When part or all of the building falls outside of those prescribed methods those portions fall under the IBC, the building code, which is basically "engineering required".... late to work, again

Thanks, hopefully you can sidestep some of the mistakes I've made along the way if I'm open with them and their lessons. It was a long one today. We made a replacement beam for that oopsed one and sawed out a white oak sill this morn then back to the woods and dropped a couple of red oaks for top plates. One had quite the crown, it was 7:30 before we got that cleaned up and out of the woods. If the weather holds tomorrow we'll start chainsaw milling that into a 40' 10x12.

When the engineer goes to analyze your frame, he will use material properties for the wood you are using. Sometimes, for simplicity, he'll use properties for the weakest wood you are using. For example a frame where white oak, mixed oak, walnut, and beech are used, the engineer did his calculations using the properties of the beech.

As a Building Inspector I have found that because an Engineer has stamped the plans does not guarantee that that the design complies with code....Moral of the story - check and double check.

Exactly, double check one another;I've been sort of waiting to see if this raised a flag with anyone. Brad put up a little test there. This is one of the reasons why even if you aren't the engineer, an understanding of basic engineering and the materials you are using is important, more so when you stray from typical construction. Look up the design values of the species in the post above. The inspector probably isn't going to catch something like this. It is up to the carpenter to know his materials and catch that.

An engineer friend who is now retired would sometimes stop at the jobsite to check on me and visit. If he invited me to dinner it was a good idea to take him up on it... I had an education filled evening coming and his wife is an awesome chef.